Unknown species of lizard found inside a gliding dinosaur's stomach

A near complete fossil of a lizard has been found inside the stomach of a microraptor, a kind of feathered dinosaur that lived around 100 million years ago.

The lizard must have been swallowed whole shortly before the microraptor died and was fossilised. It was swallowed head first, in the same way that many living birds and reptiles swallow prey.

The lizard turns out to be a new species and has been named Indrasaurus wangi by Jingmai O’Connor at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing and her colleagues. The name refers to a Vedic legend in which the god Indra was swallowed by a dragon during a great battle.

Microraptors, first discovered two decades ago, looked very bird-like apart from their teeth but had feathers on their legs as well as their arms, and were capable of gliding and maybe even powered flight, says O’Connor. “This is an independent origin of flight separate from birds,” she says. “It flew with four wings.”

Many researchers think they were tree climbers, but O’Connor disagrees. “I think microraptor was not a tree climber but rather lived on the ground but that’s controversial,” she says. “The Jehol where they lived was a forested lake environment.”

This is the fourth microraptor fossil found with identifiable stomach contents, so we know they fed on mammals, birds, fish as well as lizards. Other studies have shown that at least some of these animals had black feathers.

The microraptor and lizard are the latest of a treasure trove of fossils to emerge from northeastern China. Here a series of volcanic eruptions between 130 and 120 million killed many animals. Some were entombed in ash at the bottom of lakes and exquisitely preserved.

Other fossil treasures from the region include fossilised stick insects whose fragile wings are still clearly visible.

Journal reference: Current Biology, DOI: 10.1016/j.cub.2019.06.020